This disclosure relates to orthodontic brackets, and, more particularly, to orthodontic brackets configured for initial use as buccal tubes and each having a removable cover for retaining an archwire within an archwire slot and allowing the bracket to function as a conventional bracket with an open archwire slot when the cover is removed.
Orthodontic treatment generally comprises dental work to correct irregularities of the teeth or of the relation of the teeth to surrounding anatomy. The irregularities may involve malocclusions with varying degrees of severity. Class 1 malocclusions, for example, may involve spacing irregularities such as excessive crowding or diastema (a gap between two adjacent teeth). Class 2 malocclusions may involve overbite conditions where the upper anterior teeth project labially over the lower anterior teeth. Class 3 malocclusions, in contrast, may involve underbite conditions where the upper anterior teeth close within the lingual side of the lower anterior teeth. For these and other observed irregularities, treatment typically involves installation of braces or mechanical aids for repositioning the teeth into correct orthodontic alignment.
Braces generally include orthodontic brackets configured for attachment to the labial or lingual surfaces of the teeth or for attachment to metallic bands secured around the teeth. The brackets typically include archwire slots within which a flexible yet resilient archwire may be engaged. Each bracket is typically bonded to the tooth surface so that the bracket's archwire slot is oriented for engagement with the archwire. Various techniques are used for orienting the brackets. For example, an edgewise appliance comprises braces whereby each bracket is oriented and bonded to the tooth so that the archwire slot is perpendicular to the long axis of the root of the tooth. Alternatively, a straight-wire appliance includes braces whereby each bracket is oriented and bonded to the tooth so that the archwire slot is parallel to the occlusal plane (the plane of the biting surfaces of the teeth).
The archwire is typically a curved metallic wire having a rectangular or circular cross section that is bent or twisted prior to engagement with the brackets. The memory or restoring force exerted by the archwire upon the brackets serves to move the teeth into the desired alignment. Throughout the duration of orthodontic treatment, the orthodontist periodically adjusts the shape of the archwire (as well as the configuration of other attachments such as elastic bands and so forth) to achieve the correct orthodontic alignment.
The orthodontic brackets most commonly used on the teeth along the dental arch incorporate tie wings or extensions that project upwardly and downwardly in a gingival-occlusal orientation and require the use of ligatures or ligating modules to hold the archwire within the archwire slots. The ligatures or ligating modules are typically donut-shaped elastomeric rings or wires that are stretched around or twisted around the tie wings.
The distal ends of the archwire are typically anchored at each end of the dental arch in an orthodontic bracket commonly referred to as a buccal tube, which is attached to the surface of a terminal or anchor tooth. A buccal tube generally provides an anchor or termination of one of the (two) distal ends of an archwire when the archwire is in position, generally spanning the dental arch from the rear molars on one side mesially toward the sagittal plane (or midline of the face) and then distally toward the rear molars on the other side. A buccal tube generally provides a tubular opening that is typically substantially rectangular in cross section within which an end of an archwire may be inserted.
Anchor teeth are typically the rearmost molars in the dental arch and are most commonly the first (or six-year) molars during initial orthodontic treatment. Once the patient's second pair of rear molars (or twelve-year molars) fully erupt and become available as anchor teeth, the dentist may desire to include those newly erupted molars into orthodontic treatment by using them as anchor teeth and changing or converting the buccal tubes on the first molars to orthodontic brackets having open archwire slots.
Convertible buccal tube brackets are available which are intended to eliminate the need for removal of the buccal tube brackets and mounting of replacement open archwire slot brackets on the same molars. Thus, the successful use of convertible buccal tube brackets may eliminate potential damage to the molar enamel, reduce patient chair time, and reduce the cost of orthodontic treatment.
Several different convertible buccal tube orthodontic brackets have been designed. However, most of those have less-than-desirable designs, incorporating features requiring prohibitively expensive machining operations or comprising multiple separate parts, which in turn increases the number of failure modes and disadvantages with such brackets. Other designs have been rejected in the marketplace due to poor quality or poor design, a lack of available features, difficulty of use, or other factors.
What is needed, therefore, is a convertible buccal tube orthodontic bracket that incorporates a removable archwire slot cover and that offers a different style of bracket than those available today.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings.